With advancements in solid state technology and
television sets changing over to transistorized horizontal sweep circuitry,
sweep tubes were becoming in short supply by the middle of the 1970's. The
original FT-101 transceiver as originally equipped from the factory came with
Green Banded TOSHIBA finals and there were perfectly matched for the job
intended. At the time they were inexpensive and plentiful and used in just
about every television set in the country. With the changes in technology
Toshiba finals started to disappear by the mid 1970's. Yaesu then changed to NEC
brand final amplifier tubes in their later production of the FT-101E and FT-101F
transceivers.

Look into PA Tank Coil
12BY7
CIRCUIT

In a search for a suitable replacement sweep tube Milton
Lowens of the Fox Tango club reached out to Korea for replacement
tubes which he offered to the club with the Fox Tango Brand name and Logo.

Proper Transmitter tune up.

Yaesu technical bulletin on the proper transmitter tune up. (This is all fine
and dandy nice to know info.) Let me however make one very big suggestion
to you the reader regarding item step "E" in this note.
Always, always! Leave the transceiver meter
switch in the (I.C.) power amplifier current position allowing you to monitor
your current on the P.A. tubes. This is the only indication you have should
something be going wrong in this stage of the transceiver. The 6JS6 tubes,
while still available from many sources are getting to be very expensive.
Back in the days when this bulletin was written by the Yaesu staff, tubes were
$8 a piece. Now they are nearly 10 times that amount from some sellers.
So we recommend to you in regards to step "E" that you always, now and for ever
more as long as you attempt to run an FT-101 of any model, that you should
watch the I.C. final current during the entire tune up procedure, while
using an external meter to watch for your power output. This will
basically tell you everything you need to know as to what is going on inside the
PA / power amplifier stage. Idle current should roughly be 50 to 60ma, keyed
down on SSB mode with no modulation applied. You can tell other thing about what
is going on in the PA by watching your current meter, should the I.C meter
start jumping around erratically during tune up, it is safe to assume your
PA is oscillating and in need of neutralization. If the current starts to
creep up during key down periods, you may have the classic symptom of a leaky
coupling capacitor from pin #7 the plate of the driver tube, and the list goes
on. So watch I.C. all the time an only if you are in a real pinch and have
no other meter available to you, then you might use the Power Output (P.O.)
feature on this rig, keeping in mind there is a control on the back of the
transceiver to adjust the sensitivity of the circuit for the meter to work. So
it's all relative output, in other words the meter has no real meaning at that
point other then to show you maximum smoke! And we don't want that! Hope
that helps some of the new folks attempting to tune the FT-101. If you would
like to save the tune up use this link and save to a folder

Other Models of the FT-101 were sold in Japan for the
limited power requirements of the Japanese licensee. To fill this need
there was an FT-101S, FT-101BS, and FT-101ES. These rigs were sold with
only one 6JS6C final amplifier tube, with a normal rated power of 10 watts, and 50
PEP. From the specifications I can read it appears as though the
FT-101S/BS/ES models ran CW power of 20w (A1) and SSB Phone of 20w (A3J)
with only 300 volts to the final amplifier stage as per JARL specifications.

For those amateurs in
the states, above you can get a rare look into the FT-101ES

single tube version
transceiver. The "ES" model is seldom ever found outside of Japan.

With the addition of
the power up kit,

power could be increased to that of an FT-101E

FT-101 vs. FT-101S

(Japan low power version)

Some interesting comparisons of the low power
transceiver

FT-101S Single tube PA

FT-101PA

High Voltage

FT-101 Vs. FT-101S

Note the 3 Ohm 30w
resistor

in the
filament circuit of the FT-101S

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